Automatic control apparatus for direct-current arc welding



April 8, 1941. J TYRNER 2,237,894

AUTOMATIC CONTROL APPARATUS FOR DIRECT-CURRENT ARC WELDING Filed NOV. 2, 1959 6 Sheets-Sheet l 1 [Hill III]! INVENTOR.

ATTORNEYS.

Aprii 8, 1941. J TYRQER 2,237,894

AUTOMATIC CONTEOL APPARATUS FOR DIRECT-CURRENT ARC WELDlNG Filed Nov. 2, 1939 Q3 Sheets-Sheet 2 INVENTOR.

ATTORNEYS April 8, 1941. J TYRNER 2.237.894

AUTOMATIC CONTROL APPARATUS FOR DIRECT-CURRENT ARC WELDING Filed Nov. 2, 1939 6 Sheets-Sheet 3 TIME]? if 42mm ATTORNEYS J. TYRNER April 8, 1941.

AUTOMATIC CONTROL APPARATUS FOR DIRECT-CURRENT ARC WELDING Filed Nov. 2, 1939 6 Sheets-Sheet 4 ATTORNEYfi J. TYRNER A ril 8, 1941.

AUTOMATIC CONTROL APPARATUS FOR DIRECT-CURRENT ARC WELDING Filed Nov. 2, 1939 6 Sheets-Sheet 5 IN VENTOR. A 7 $04 ATTORNEYS, v

April 8, 1941, TYRNER 202 437,894

AUTOMATIC CONTROL APPARATUS FOR DIRECT-CURRENT ARC WELDING Filed Nov. 2, 1939 6 Sheets-Sheet 6 MfHCU/E'Y SWITCH w INVENTOR.

ATTORNEY3 Patented Apr. a, 194i L APPARATUS FOR 6 (Claims.

The present invention relates to the art of direct-current arc welding and has particular reference to an improved automatic control apphmtus for use in that art.

Wherever welding is carried out at points remote from the motor-generator unit, as in the case oi shipyard and structural work, boiler and tank shops, pipe lines, steel mill work, etc., a dots and substantial saving in. time is efiected hy the use oi control apparatus which automatically starts such unit running at vthe hec'limina of a welding operation and automatically stops it when Welding is interrupted. Such control apparatus should operate in response to circult establishment at the work for starting purposes, and in response to circuit interruption at the work for stopping purposes. However, whereas it should cause the motor-generator unit to start running practically at the same instant contact is made between worl: and welding electrode with the view to drawing the are, it should operate to stop such unit with a certain time lag upon completion ofthe welding operation. This time lag, which may for example be from thirty to a hundred and twenty seconds, is necessary in practice to insure that the motor-generator unit he kept 1311.01 ing through the usual circuit interruptions at th work during welding.

The fundamental object oi the invention is to provide an automatic control apparatus of the character mentioned, which is simple in con= struction and reliable in operation.

, Generally stated, the invention contemplates the use, in association with the direct-current arc welding circuit and the motor-generator unit supplying the direct current to such circuit, of an automatic control apparatus comprising a transformer-relay unit operatively associated with simple elements including a rotary member horihally hissed for rotational release from its normal position, an electric timing device for e'fiectinlg a timed rotation of the rotary member himllar characters refer positioned to normally engage the rotary memher, which is appropriately connected mechani= caily with the retractable armature to efiect its disengagement from such shaft upon armature attraction by the relay core and its engagement with such shaft upon retraction of the armature. Both the motor-generator unit and the electric timing device have their operation controlled by the switching means, which are actuated by the rotational movements of the rotary member from and back to its normal position.

The invention will be understood from the fol. lowing description taken in conjunction with the accompanying drawings in which Figs. 1 to 3 are schematic views of a form of apparatus embody ing the invention showing three diflerent positions of its movable parts; Figs. 4 to 6 are similar views of another form which diflers from the preceding with respect to its switching means; Fig. 7 is a side elevation of a practical embodi= merit of the invention with switching means omitted; Figs. 3 and 9 are respectively front and plan views of the latter embodiment; Figs. "iii and ii are respectively horizontal sections taken on the lines iii-l0 and ii-li of Fig. e; i2 is a iragmentary view more clearly illustrating certain details shown in Figs. h and h; and Figs. 13 and i i are wiring diagrams having reference respectively to the switching means of Figs. 2 to 3 and to the switching means of 4 to (i.

to similar palms throughout the various figures.

Referring to Figs. 1 to 6, the two forms of control apparatus illustrated in these figures are seen to comprise coon elements inclusive of a transformer-relay unit generally indicated by the numeral 0, a lever generally indicated by ing it is wound to embrace both the transformer core 77 and the relay core 9 and therefore serves both as a transformer secondary and as the magnetizing winding for the relay core ii. Also ineluded in the transformer-relay unit l is an armature it? which cooperates with the relay core 9. The lever 2 is of the type having two plvotal arms to and 2b on either side of its fulcrum or supporting shaft is. On one arm 2:; is

2 ass-zest carried the armature l2, while on the other arm 2b is carried a stub shaft or pin l on which is pivotally mounted the disc 6 in theapparatus of Figs. 1 to 3 and the sector 6 in the apparatus of Figs. 4 to 6. A spring l6 additionally included as a common element retracts the arma-' ture l2 from its position of engagement with the relay core 6. As shown, the electric timing device 6 has a shaft ll positioned to rotationally engage the disc edge la in the apparatus of Figs. 1 to 3 and the sector edge to in the apparatus of Figs. 4 to 6 upon such armature retraction.

A further element common to the two forms of control apparatus illustrated in Figs. 3. to 6 is a second spring it for rotational release of the rotary member of either apparatus from its normal position of rest on the lever 2. Appropriate means hereinafter described are employed in each apparatus for checking this rotary member release by the spring 86, which takes places simultaneously with the pulling down of the armature i2 into its position of engagement with the relay core t, by which armature movement the rotative edge of the rotary member in either apparatus is lifted out of engagement with the shaft ill. Thus, coincident with attraction of the armature i2 by the relay core 9 is an actuation by the spring it} in the apparatus of Figs. 1 to 3 of the disc 6 from its position of Fig. 1 to its position of Fig. 2 and in the apparatus of Figs. 4 to 6 of the sector 5 from its position of Fig. 4 to its position of Fig. 5. Subsequent retraction of the armature 82 by the spring i6 efiects a lowering in the apparatus of Figs. 1 to 3 of the disc 6 into its position of Fig. 3 and in the apparatus of Figs. 4 to 6 of the sector l into its position of Fig. 6. At this moment the spring i6 is effective in pressing the disc edge 43a in the apparatus of Figs. 1 to 3 and the sector edge 6a in the apparatus of Figs. 4 to 6 against the shaft ll, which thus enables such shaft to rotate the rotary member of either apparatus back to its normal position of rest on the lever 2, the disc 3 in the apparatus of Figs. 1 to 3 being returned to its position of Fig. 1 and the sector '5 in the apparatus of Figs. 4 to 6 to its position of Fig. 4. This rotation of the rotary member of either ap paratus by the shaft l'l stores energy in the spring l9, which is thus made ready to efiect its own rotary member release in immediate response to armature attraction by the relay core 6, as already explained.

, It is the function of the rotary member in apparatus of this invention to actuate in turn appropriate switching means by its rotational movements. Such switching means have for their main purpose to afford circuit control of the motor included in the motor-generator unit used for welding and circuit control of the motor included in the electric timing device, these two motors being started as a result of the rotational movement of the rotary member from its normal position and stopped as a result of the rotational movement of the rotary member to its normal through the usual magnetic starter included-in I welding equipment. As will hereinafter more particularly appear in connection with the diagrams of Figs. 13 and 14, both the operation of although this particular control should not be Y a practical standpoint, as will hereinafter be explained. It is evident that there are various the motor-generator unit and the operation of the electric timing device are controlled in this manner by each of the two switching means peculiar to the two forms of apparatus illustrated in Figs. 1 to 6. The switching means of Figs. 1 to 3 also make use of such starter in controlling the energization .of the transformer primary, while the switching means of Figs. 4 to 6 are capable of efiecting this control with or without the assistance of such starter, a separate switch effecting it alone being included in the switching means of Figs. 4 to 6 for the purpose of illustra'ttrating this possibility. As will hereinafter be= come apparent, the manner in which control of the energization of the transformer primary is efiected depends on its circuit connections, each of the two switching means peculiar to the two forms of control apparatus illustrated in Figs. 1 to 6 being of a type adapting it to efiect the various controls in conjunction with the usual magnetic starter, if desired.

Each of the two forms of control apparatus illustrated in Figs. 1 to 6 will now be separately described.

Referring to Figs. 1 to 3, the switching means generally indicated by the numeral 26) in these figures comprise a fixed contact 2i and two movable contacts 22 and 26 adapted to cooperate with the fixed contact 2i. In operation, these three contacts substantially duplicate those of the usual push-button device employed with the aforementioned magnetic starter, as will hereinafter. become apparent. iwo pins 25 and 26 are provided on the disc 6. Pin 25 normally holds the movable contact 22 out of engagement with the fixed contact 2i (Fig. 1), but allows these two contacts to close practically instantaneously by its rotation with the disc 5 under the action of the spring to. Pin 26 checks this rotational release of the disc 6 by its engagement with the fixed contact 2! and at the same time connects the fixed contact 2! to the movable contact 26 by its common engagement with these contacts (Fig. 2) Armature attraction by the relay core 9 thus effects connection of the fixed contact it with each of the movable contacts 22 and 26. Subsequent armature retraction by the spring l6 has itself no influence on either of these connections (Fig. 6) but the rotation. of the disc 6 by the timing device shaft it initially interrupts the connection of the fixed contact 2! with the movable contact 26 by causing the pin 26 to move out of its contact-making position of engagement with the fixed contact 21 and finally interrupts the connection of the fixed contact 2! with the mov-= able contact 22 by causing the pin 25 to move into its contact-breaking position of engagement with the movable contact 22, each pin being restored by this timed rotation of the disc 6 to its normal position (Fig. 1). While the disc d is shown as carrying two pins 25 and 26, it is evident that a single pin can be used to accomplish each of their purposes, desired.

- Referring now to' Fig. 13, the rectangle 21 indiindicated by the rectangle 39, and e. push-button device indicated by the rectangle 3!. The usual direct-current generator 32 for supplying the welding current and s. t l-phase motor to 01 driving such generator are shown as comprising the unit Operation of the unit 28 is con trolled through the starter ,ovhich for this purpose has three input terminals 16 to it con-= "particularly described. The welding: circuit sure oiled with current from the generator 82 includes the work it and the welding electrode it thereon,

the usual conductors to being shown connecting these elements to the generator terminals.

The starter it includes three pilot circuit wre, minels Pi to P3. It i'urther includes at holding coil to" cool on interlock cl. Both the circuit connections 39 end the interlock ii are megtactically controlled by the coil st, which es= tohlishes such connections and closes the inter= loch ll, when it is energized, and interrupts such connections end opens the interlock ill, when.

it is oeenergizeil. As shown, one input terminol ll leeris directly by c conductor iii to one pilot circuit terminal Pl. Conductors E56 connect the interlock ill between the some input it one s second pilot circuit terminsl P2, while con rluctors Bl connect the holding coil to hetween V o second input terminal 12 end the third pilot circuit terminol P3.

The clerics 30 has three terminels iniicoteol Ti to T8. The start button 60 cool with contacts 66c one"! 6%, which are normally; The stop hutton ll cooperates with con tests Bio curl til, which are normelly closed. he mole clear hr the conductors 62, two ter-= initials Ti oncl T2 are respectively connected to one storhhuttonwontect its one] to one stop huttoncontoet ilo, while the third terminol Til is connected to hoth the second stert-hutton= contact 3th one the second stochutton-contoct ii to. it is understood thot the two buttons l0 cool it me of the tyne adopted when releesetl To? the onerstor to he retroctecl to their nominl cosh tions, as schematlcslly represented by the springs Still reierrlng to Mg. 13, the terminals Pi and P2 ere respectively connected hy conductors and 55 to the terminels Tl end m, the terminol "in is connected by c conductor ill! to the movable contact 22, end the fixed contact it is con nected icy s conductor 59 to the terminal P8. In the absence of the eutomstic control sogceretus 2'8, o direct connection would, according to stenciard practice, he provided hetweenthe terminals T3 and P3. A switch connected by conductors 89 across the normally open contacts El and 22 of such opparatus is thus s en to be included as an accessory in the wiring diagram of Fig. 13 to enable obtaining this connection 101' normal oneratlon oi! the push-button device 38. with the switch I closed, the holding coil 46 is energized by pressing the start button 40, which connects such-coil through the closed contacts we end no of such button across the input terminals it end I? (and hence across one phase oi the current supply 86). Since this energizetion of the coil to results in a. closing of the interlock t'l,

such coil is further connected across the seme terminals It and 12 through the normally closed stop hutton-contects Bio and Gib, which pro vents its deenergizotion upon release of the hut ton so. The coil 43 thus remains energized un til the stop button M is depressed, at which moment it is obviously oeenerelzeo by an open-' ing oi the contacts Ma and ilo of such button, the ooening of the interlock ti accompanying this cieenergizotion preventing its reenerelzotion upon release oi the button it cool keeping it de energised until the start button is eesin oepressecl. Since the coil to by its enersizetlon one cleenereizntion iunctions resoectively to establish and interrupt the circuit connections 89, it is clcer that the push-button device at can be on excited in the usual manner to close or open the sterter 3t and thus control the operation oi the motor-generator unit ii the switch Elh is hem closed.

0n the other hand, the switching means it) are ooeptecl to chest their sutomntic control of the operation of the unit it, with the switch to open. Also included in the connections oi such moons is e, conductor 62 connecting the movolole contact 2 3 to the terminal Pi Flotation ol'relecse oi the slice i under the notion oi the spring l9 energizes the coil CEO by connecting it through the contectslll one 26 ocross the input terminm In and ill (one hence across one nheee oi the current supply 8t), which contacts are close-cl incident to such science in; the notion oi the oinBO. The closing oi the interlock (ll he this energicotlon also connects the coil (16 across the some it one 12 through the contacts 2i and 222', which closetl he the ection oi the oln 25 at the very stnrt oi the rototionloy the sprint; l9, one throuoh the stop=hntton=contocts Lilo one 6th, rennin closecl throughout the onerotlon oi the onto hectic control oposrntns 21!. Ehereiore, the coil 66 is prevented from deenergislnc when the con-= tocts 2i cool 26 are openecl hy the action oi the oin to incident to the rototlon oi the G or the shaft ll. It is necintsnnecl energ zed until the o G by this rotation is retur ed to its nor= noel position, at which moment it in oh nously oeenemisecl he on opening oi the contacts 2 i one 22 on the notion oi the pin 25, the opening of the interlock All caused by this cleenergizotlon incuring its heins reenereisesl or only oos= slble closing oi time contsctc 2i and 22 heiore the disc 6 is sgoin rototionslly released by the spring ill. Since the coil it by its energisetlon end deenersisetion respectively functions to estohlish and interrupt the circuit connections 88, it is clear that the switching means 20 select eutomotic control or the operation of the stei ter to end hence the desired automatic control therethroush ol the operation of the unit if the switch is kept open.

A second switch M is included es en accessory in the wiring slicer-em of Fig. 13 to render the electric timing device 6 capable or incapable oi operation, as desired. Conductors it connect the motor terminals of the device 6 in a series circuit with the switch 6t across two starter out put terminals Oi and 02. By these connections, with the switch 9-41 closed, operation of the device 6 is obviously controlled by the starter 3i? which, when closed, connects it across the input terminals II and I2, (and hence across one phase of the current supply 38) and, when open, disconnects it from the same terminals It and 12. From this it is apparent that the switching means 20 by their automatic control ofthe starter Siii effect the desired automatic control of the operation of the device 6, with the switch til open, the device 6 being operated simultaneously with the motor-generator unit 29. The usual control of the operation of such unit by the push-button device 3i is efiectedwith the switch 3 open, which permits such control without operating the electric .timing device 5.

The connections of the transformer primary it according to the diagram of Fig. 13 are provided by conductors 65 connecting one starter input terminal Ii directly to the corresponding output terminalOl and a second input terminal 12 through such primary to the corresponding output terminal 02, a third switch El connected in one of these conductors being included as an accessory in such diagram to render the transformer primary it) capable or incapable of energization, as desired. By the conductors $6, it is apparent that the transformer \primary in is adapted to be parallelly connected with one of the starter connections 39 in a series circuit through the driving motor 36 (i. e., one of the phases of its stator winding) across the input terminals II and I2 (and hence across one phase of the current supply 36), with the switch ti closed. When the starter is open, the transformer primary it is obviously energized in this series circuit, the small current required to efiect its energization (as a result of its high impedance) having no effect on the motor 35. On the other hand, when the starter it is closed, the transformer primary iii is deenergized by reason of short-circuit through its parallelly connected circuit connection 39. In view of this control of the energization of the transformer primary ill by the starter 30,, it is clear that the switching means by their automatic control of such starter effect the desired automatic control of such energization, with the switch til open, such primary being deenergized when the motor-generator unit 29 and the electric timing gram of Fig. 13 is designed so as to clearly outline the individual circuits necessary for proper operation of the apparatus 2? in association with the usual elements of standard welding equipment.

Iii-accordance with the invention, the transformer secondary and relay winding ii is connected in the welding circuit, as illustrated by the conductors 35.

The novel manner in which the automatic control apparatus illustrated in Figs. 1 to 3 operates will now he more fully described in connection with the schematic views of these figures and with the wiring diagram of Fig. 13, it being assumed in this description that the switch till is kept open and the switches M and ti are kept closed at all times.

Fig. 1 shows the apparatus 2? (Fig. 13) in the normal position of its movable parts. The transformer primary id is energized, since the starter 3d is open. Let it be assumed that a weldin operation is to be carried out at the work 62. The operator contacts the welding electrode ill with the work 42, which closes the welding circuit. Current is thus induced by the transformer primary it in the transformer secondary and relay winding H, which magnetizes the relay core 9. Fig. 2 shows the apparatus 271 in the position into which its movable parts, are moved at this moment, the armature l2 being attracted into engagement with the relay core 9 simultaneously With a rotational release of the disc Li by the spring 6 a, resulting in an actuation of the switching means 2@ connecting the fixed contact 25 to each of the movable contacts 22-and 2 3. This closes the starter fill, which starts the motorgenerator unit 29 running. All this is effected practically at the instant when the welding circuit is closed by the operator, so that current from the generator 32 for drawing the arc and starting the welding operation is available to the operator in the comparatively short period required for the motor-generator unit 29 to gather speed. The closing of the starter 3e further starts the electric timing device 6 and deenergizes the transformer primary it, but the directcurrent flow from the generator 32 energizes the winding it during the welding operation, which is thus carried out with the armature It in engagement with the relay cores and the disc 6 out of engagement with the rotating shaft Ii.

device 6 are operated and energized when such unit29 and device 6 are at rest. The usual control of the operation of the unit 29 by thepushbutton device 3! is efiected with the switch 57 open, which permits such control without energizing the transformer primary It.

It should here be noted that the wiring diagram of Fig. 13 is not one to be regarded as illustrating the simplest connections to be used in practice. For example, the conductor 65 leadingfrom the starter input terminal It may be directly connected to that timing device terminal t which is connected through the switch 6 3 to the starter output terminal OI, in which event the switch 51 would be omitted and the switch t6 would serve both its own specific purpose and the purpose of the omitted switch 67. Furthermore, it is possible to operate the apparatus 2? without the push-button device 3|, in whichevent the conductor 51 would be directly connected to the starter pilot terminal P2 and the three switches 80,- St and 6'? omitted. The wiring diathe welding operation.

When the welding operation is completed, the welding circuit is opened by the breaking of the are between the work 52 and welding electrode 86. The relay core a is demagnetized by deenergization of the winding ll. Fig. 3 shows the apparatus 27 in the position into which its movable parts are moved at this moment, the electric timing device 5 being now efiective in rotating the disc 6 because of retraction of the armature 82 by the spring H5. The opening of the contacts 2 i and 28 hasmo effect on the starter 38 at the start of this-rotation, but combined with theultimate opening of the contacts 2i and .in response to another welding demand upon the generator 32.

If for any reason whatever the welding circuit is broken before a welding operation is completed, the apparatus 21 at once assumes the position of its movable parts shown in Fig. 3, but its transition to the position of Fig. 1 is timed because of the rotation of the disc 4 by the shaft II. The stopping of the motor-generator unit 29 is thus delayed by the period required for the disc 4 to rotate from its position of Fig. 3 to its position of Fig. 1, which enables the operator to readily restore the welding arc at any time before completion of this notation. Whenever welding is thus interrupted and resumed, the reenergization of the winding H caused by the closing of the welding circuit results in a practically instantaneous return of the apparatusZ'l to the position of its movable parts shown in Fig. 2, the disc 4 being reversely' actuated by the spring ts from the .position reached by rotative association with the electric timing device during welding interruption. This means that the stopping of the motor-generator unit 29 is delayed on each occasion of welding interruption for the same period, which is the time required for the rotation of the disc 4 from its position of Fig. 3 to its position of Fig. 1. This period may obviously be of any predetermined duration and depends cn such factors as the speed of the electric timing device 8, the ratio of the radius of the shaft IT to the radius of the disc I, and the angular distance between the pins and 28.

In using the apparatus 21 to carry out a welding operation, it should be noted that the operator will in general simply contact the welding electrode with the work momentarily so as to effect the closing of the starter 30, after which he will allow suflicient time for the motor-generator unit to gather speed, whereupon he will again contact the welding electrode with the work for the purpose of drawing the welding arc. The

' armature M will be retracted by the spring i6 and th disc d rotated by the device 5 following the initial momentary closing of the welding circuit, but it is clear from theforegoing description that the apparatus 21 will at once be caused to assume its welding position of Fig. .2 by the subsequent closing of the welding circuit to start the welding operation, the rotation of the disc 4 during the comparatively short period the welding circuit is permitted to remain open by the operator being obviously insunicient to stop the motor-generator unit. Of course, the operator may, if he chooses, leave the welding electrode in contact with the work during the period allowed ter the motor-generator unit to gather speed, but in this case he must exercise proper judgment regarding the length of such period to prevent sticking of the welding electrode to the work, which if allowed to occur would obviously make the drawing of the are more or less troublesome. The use of the apparatus 21 in the latter manner retains it in the welding position of Fig. 2 through the allowed period of welding.

electrode contact with the work preceding the welding operation, as is evident from the fact that only a fraction of the final value of the current supplied through the winding II from the generator is suflicient to hold the armature I 2 in engagement with the relay core 9, thebrief period required for this condition to be attained in the welding circuit being more than compen- Referring to Figs. 4 to 6, the sector '5 is seen to be rotatively associated with gravity-drop switching means generally indicated by the numetal. 69. Included in these means is a bracket 10 pivotally mounted with the sector 5 on the 5) from their position of Fig. 4 first by the pin II and thereafter by gravity to their position of Fig. 5, in which they are maintained by the pin 15. On the other hand, the sector rotation by the shaft I1 causes the switching means 89 to be rotated from their position of Fig. 6 first by the pin I5 and thereafter by gravity to their position of Fig. 4, in which they are maintained by the pin ll. Each of these rotational movements of the switching means 69 is effective in actuating each of the two mercury switches H and 72, as will hereinafter be more particularly 7 described.

Referring now to Fig. 14, the rectangle 11 indicate's the apparatus of Figs. 4 to 6, which in this instance is shown associated with the heretofore described elements of standard welding equipment exclusive of the push-button device.

One mercury switch I! is normally open and is' effects both a control of the operation of the motor-generator unit 29 and a control of the operation of the electric timing device 8 through the starter 30. On the other hand. the switch 32 is adapted to function alone in effecting a direct-control of the energization of the transformer primary III. The transformer secondary and relay winding II is again shown connected in the welding circuit, as required by the invention.

Fig. 4 shows the normal position of the switching means 69. The starter 30 is open and the transformer primary ill is energized, since the switches H and 12 are open and closed, respec tively. A closing of the welding circuit energizes the transformer secondary and relay winding II with a resulting armature attraction by the relay core 9 and a practically instantaneous rotation of the switching means 69 under the influence of the sector release by the spring l9 into their D s'ition of Fig. 5. This closes the switch II and sated by such factors as the time taken by the the closing of the starter 30.

' transformer primary Ill to deenergiz following opens the switch I2. theclosing of the switch 1| closing the starter" The imit 29 and the device 6 are started, while the transformer primary do is deenergized, the generator 32 now becom ing the source depended upon to energize the winding II with the welding circuit closed, as in the case of the apparatus of Fig. 13. Any opening of the welding circuit with resulting armature retraction by the spring [6 will effect a lowering of the switching means 69 into their position of Fig. 6, which will thus cause them to be rotated from this position under the influence of the sector rotation by the shaft ll. However,

' there will be no actuating efiect on the switches ii and 12 unless the opening of the welding circuit is unduly prolonged, the reestabllshment of the switching means 69130 their position of Fig. by subsequent closing of the welding circuit being possible at any time prior to their eventual drop into their position of Fig. 4. This opens the switch H and closes the switch 72, the opening of the switch 1! opening the starter 3d. The unit 29 and the device 6 are stopped, while the transformer primary I8 is reenergized.

From the foregoing description it is clear that each of the two forms of automatic control apparatus illustrated in Figs. 1 to 6 is fundamentally characterized by the same operating features. If desired, the transformer primary it could obviously be connected for use in the apparatus of Figs. 4 to 6 in the same manner as it is shown connected (in the wiring diagram of Fig. 13) for use in the apparatus of Figs. 1 to 8, in which event the switch ll would cooperate with the starter 39 in controlling its energization and the switch i2 would be omitted as unnecessary. Fmthermora-the usual push-button device could also be associated with the apparatus of Figs. 4 to 6, as is evident to those skilled in the art.

It has already been mentioned that a control of the energization of the transformer primary is not actually required in apparatus of this invention. In the absence of this control, however, the transformer primary (then permanently connected to the current supply) must be made of much heavier wire or even operated with resistance in order to withstand the increased fiow of alternating current from the current supply during the period of welding current flow in the transformer secondary and relay winding, as caused by saturation in the transformer core. From a practical standpoint, therefore, a control of the-energization of the transformer prithe relay core -9 should be so dimensioned and positioned as to cause it to register perpendicularly with the transformer core part la, as made clear by the horizontal sections of Figs. 10 and 11. Thecharacter ml (Figs. 8 and 10) has reference to the middle leg of the transformer core part Ia, while the character m2 (Figs. 8 and 11) has reference to the middle leg of the relay core 9. As best shown in Figs. 10 and 11, two windings l0 and M respectively surround the middle legs mi and m2. Theinner winding I0 is a transformer primary made to embrace only the middle leg ml while the outerwinding ll isa transformer secondary and relay winding made tn embrace both of the middle legs ml and m2.

The making of the transformer core 7' in the two parts to and lb makes possible the positionine. of the two windings Hi and ll as described, such transformer core parts being thereafter permanentlysecured to one another by suitable clamping' means 84. Other clamping means 85 may be used to securely hold the transformer secondary and relay winding ii in place. Par

allelly extending angle members 83 may be used on .the upper surface of the outer legs of the relay core a for greater rigidity of the unitary structure shown. 5

Referring to Figs. '1 to 9, the relay core 8' is seen to cooperate with a bar-like armature l2.

' This armature issecured to the base portion of a U-like carrier 8? whose end portions are shaped to provide bell-crank levers 2'. These levers are respectively mounted on the outer end portions of a horizontal shaft 841', which may be fixedly secured through forward extensions 86a formed on the vertical flanges of the angle members 86. As will appear in the description following, the two levers 2' have the same function together as the single lever 2 of Figs. 1 to 6.

Still referring to Figs. 7 to 9, the armature l2 cooperates on'one side of the transformer-relay unit with a rotary member 5', which in turn co-= operates with an electric timing device 6' apprm end of a tension spring it, the upper end of which is attached to a pin to extending laterally from the rearwardly extending arm 22: of the other of the levers 2' (see Fig. 12). The spring it thus functions through this one of the levers 2 to restore the armature t2 to its normal nil-- each of the levers 2' to lower the member 5 into its operative position of rotational engagement with the timing device shaft ll. As best shown in Fig. 7, the member 5' is rotationally released from its inoperative position of engagement with the timing device shaft it by a volute spring if) having its inner end anchored to the hub h and its outer end anchored to the topof the W former relay unit. A suitable stop iii secured to such top checks such release.

Although no switching means are shown to be associated with the rotary member 5' in'the uni= tary structure of Figs. 7 to 12, itis evident that any one of various forms can be used adapted to cooperate with such member in efi'ecting the circult controls heretofore described in connection with th schematic views of Figs. 1 to 6.

The relative position of the rectangle 27! in Fig. 13 and of the rectangle W in Fig. 1.4 has reference. to no particular point of connection of the control means of the invention in the welding circuit, it being understood that such control a means would in practice be installed with the rest of the accessories close to the motor-gen erator unit. I

It is to be understood that the invention is not vto be limited to the illustrativ embodiments herein particularly described, but may be carried out in other ways within the purview of the claims.

What is claimed is:

1. The combination with a direct-current arc being connected .in said circuit. a transformerv primary embracing the transformer core alone for energizing said transformer secondary and relay win-ding upon closing of said circuit, a retractable armature cooperating with the relay core, a rotary member normally biased for rotation from its normal position, an electric timing device for rotationally restoring said member to its normal position, said device having a normally stationary rotary shaft normally engaging said member, mechanical means operatively connecting said member with said armature to effect movement of said member out ofengagement with said shaft upon attraction of said armature by the relay core and movement of said member into engagement with said shaft upon retraction of said armature, and switching means operated by said member for controlling the operation of said unit and the operation of said device, said switching means being actuated by the rotational movements of said member from and back to its normal position.

2. The combination with a direct-current arc welding circuit and a motor-generator unit for supplying the direct current to said circuit, of

an automatic control apparatus comprising transformer and relay cores, a transformer secondary and relay winding embracing both of said cores, said transformer secondary and relay winding being connected in said circuit, a normally enersized transformer primary embracing the transformer core alone for energizing said transformer secondary and relay winding upon closing of said circuit, a retractable armature cooperating with the relay core, a rotary member normally biased for rotation from its normal position, an electric timing device for rotationally restoring said member to its normal position, said device having a normally stationary rotary shaft normally engaging said member, mechanical means operatively connecting said member with said armature to effect movement of said member out of engagement with said shaft upon attraction of the armature by the relay core and movement of said member into engagement with said shaft upon retraction of said armature, and switching means operated by said member for controlling the operation of said unit and the operation of said device and for controlling the energization of said transformer primary, said switching means being actuated to start said unit and said device and deenergize said transformer pri- I mary by rotational movement of said member from its normal position and to stop said unit and said device and energize said transformer primary by rotational-movement of said member to its normal position.

3. 'The combination with a direct-current arc circuit, a retractable armature cooperating with the relay core, a rotary member normally biased for rotation from its normal position, an electric timing device for rotationally restoring said member to its normal position. said device having a normally stationary rotary shaft normally engaging said member, mechanical means operstively connecting said member with said armature to effect movement of said member out of engagement with said shaft upon attraction of said armature by the relay core and movement of said member into engagement with said shaft upon retraction of said armature, said device being connected for control of its operation by said starter, and switching means operated by said member for controlling the operation of said starter, said switching means being actuated to close said starter by rotational movement of said member from its normal position and to open said starter by rotational movement of said member to its normal position.

4. The combination with a direct-current arc welding circuit, a motor-generator unit for supplying the direct current to said circuit, and a magnetic starter controlling the operation of said unit, of an automatic control apparatus comprising transformer and relay cores, a transformer secondary and relay winding embracing both of said cores, said transformer secondary and relay winding being connected in said circuit, a normally energizedtransformer primary embracing the transformer core alone for energizing said transformer secondary and relay winding upon closing of said circuit, a retractable armature cooperating with the relay core, a rotary member normally biased for rotation from its normal position, an electric timing device for rotationally restoring said member to its normal position, said device having a normally stationary rotary shaft normally engaging said member, mechanical means operatively connecting said member with said armature to effect movement of said member out of engagement with said shaft upon attraction of said armature by the relay core and movement of said member into engagement with said shaft upon retraction of said armature, said device being connected for control of its operation by said starter, and switching means operated by said member for controlling the operation of said starter and for controlling the energization of said transformer primary, said switching means being actuated to close said starter and deenergize said transformer primary by rotational movement of said member from its normal position .and to open said starter and energize said transformer primary by rotational movement of said member to its normal posi tion.

5. The combination with a direct-current arc welding circuit supplied with welding current from a direct-current generator, an alternatingcurrent motor for driving said generator, an alternating-current source, and a magnetic starter connected between said motor and said source, of an automatic control apparatus comprising transformer and relay cores, a transformer secondary and relay winding embracing both of said cores, said transformer secondary and relay winding being connected to said circuit, a normally energized transformer primary embracing the transformer core alone for energizing said transformer secondary and relay winding upon closing of said circuit, a retractable armature cooperating with the relay core, a rotary member I normally biased for rotation from its normal position, an electric timing device for rotationally i transformer primary being parallelly connected with said starter through said motor to said source and said device being parallelly connected with said motor through said starter to said source, and switching means operated by said member for controlling the operation of said starter, said switching means being actuated to close said starter by rotational movement of said member from its normal position and to open said starter by rotational movement of said member to its normal position.

6. The combination with a direct-current arcwelding circuit and a motor-generator unit for supplying the direct current to said circuit, of an automatic control apparatus comprising transformer and relay cores, a transformer secondary and relay winding embracing both of said cores, said transformer secondary and relay winding being connected in the welding circuit, a transformer primary embracing the transformer core alone for energizing said transformer secondary and relay winding upon closing of said circuit, a retractable armature cooperating with the relay core, a rotary member normally biased for rotation from its normal position, an electric timing device for rotationally restoring said member to its normal position, said device having a normally stationary rotary shaft normally engaging said member, a lever having two pivotal arms on which said armature and said member are respectively fixedly and pivotally mounted, and switching means operated by said member for controlling the operation of said unit and the operation of said device, said switching means being actuated by therotational movements of said member from and back to its normal position.

JOSEPH TYRNER.

CERTIFICATE OF CORRECTION.

Patent No. 2,2 7 9L April 19in.

JOSEPH TYRNER. I It is hereby certified that error appears in the printed specification of the above number-ed patent r equiring correcti on asfollows: Page 7, sec- 0nd column, line 60, claim 5, forthe word "to" read -in; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of may, A. 1). 191m.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 2,257,89u. April 19m.

JOSEPH TYRNER. v

It is hereby certified that error appears in the printed specification of the above numbered patent r equiring correcti on as follows: Page 7, sec-- 0nd column, line 60, claim 5, for the word "to" read in; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case *in the Patent Office;

Signed and sealed this 15th da of May, 1). 191m.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

